How do you figure out the efficiency of a motor and drive?

Energy efficiency is a hot topic. Our customers are continuously looking for ways to save energy, and now, in Europe, new standards are helping.

Europe is trying to save energy, and one of the ways it’s doing it is through its “Ecodesign” initiative.

By 2020, for instance, new ecodesign regulations – meant to ensure that products take into account their environmental impact from cradle to grave – on 13 product groups are projected to produce energy savings by 2020 equal to more than 12 percent of the total electricity consumption of the EU in 2009.

The newly released EN 50598-2 standard brings in two new energy efficiency classifications that manufacturers like ABB and machine builders, as well as the ultimate end user, can use to help determine the energy efficiency of the machines they build or use in order to meet these new European regulations.

The first is an IE classification for the variable speed drive, which the standard dubs a “complete drive module,” or CDM. The CDM consists of the drive and any of the other auxiliary equipment connected to the drive, like a braking chopper or EMC filter. The IE classification is similar to what motors have had – ranging from IE0 to IE4. The lower the IE number, the less efficient the CDM.

The more you know

The second new classification is an IES system classification for the “power drive system” or PDS, which is the combination of the motor and the drive together.

This is new, and is valuable because in addition to the overall efficiency classification, regulators provide in the EN 50598-2 standard a defined set of operating points at which the efficiency of the power drive system is measured. As many realize, many motors don’t need to be run at full speed all of the time, they typically run at partial loads.

These measurements at defined operating points provide that partial load efficiency values. That means you can estimate energy use for your process or machine based on their typical operating profiles. This helps with everything from buying decisions to budgeting and energy appraisal analysis. It can be used to determine the return on investment and even estimate power losses.

IES classes are defined from IES0, the lowest efficiency, to IES2, the current label for the highest-efficiency class. More IES classes will be defined in the future. These new classifications are valid for motor and drives that are within the 100 to 1,000 volts, with a power up to 1,000 kW.

Some considerations about the new IE and IES classes

One of the first things to note is that the IE classification for drives – the CDMs – is done differently than for motors. For motors, the IE classification is taken at 100 percent motor speed and 100 percent motor torque. For the CDM, the classification is taken at 90 percent frequency and 100 percent current.

As such, you can’t add a motor IE classification and a CDM classification to get the PDS IES value.

Second, making the measurements or calculations depends on what the manufacturer produces. For example, ABB manufactures both motors and drives, so according to the standard, ABB can provide separate IE values for the CDM and the motor, and the IES value for the combination of a selected motor and drive. For manufacturers who only produce the motor or the drive, the standard provides reference models. This allows those manufacturers to substitute the reference model to use in determination of a PDS IES classification.

Ready for the calculations

IE2 – that’s the efficiency of our ACS580 general purpose drive. Currently, this is the highest defined classification according to the EN 50598-2 standard. We also provide the partial load efficiency data.

But the drive also comes with even more features that help our customers save energy every day. It’s got advanced energy efficiency analyzers built into the device that help the drive save up to 10 percent more energy when controlling partial load applications. Energy efficient motors are also easily controlled, and the drive works with induction, asynchronous and permanent magnet motor.

The drive will also report daily or hourly energy use, and keep track of total energy used. The drive can even calculate money savings and how much emissions of carbon-dioxide have been reduced by using the drive. All this data helps you calculate your return on investment, and also for use in net present value calculations.

So as we see more energy efficiency standards being defined and the push from our customers, we’ll continue to develop and provide value for our customers. Power and productivity for a better world is important to us, just as it is for you.

Want to learn more about the new standard? Visit our Ecodesign website.